1. Field of the Invention
The invention generally relates to gear head wrenches and more particularly to an improved gear head wrench adapted rapidly to drive bolts into bolt-receiving structures without inducing therein substantial torsional stress.
It will be understood, of course, that as a bolt is torqued and thus "snugged-down" or tightened the head thereof is caused to engage the upper surface of a spacer normally interposed between the head and a selected bolt-receiving structure. As a consequence, frictional forces are developed between the juxtaposed surfaces of the head, spacer and structure so that torque is thus transmitted from the head to the spacer and thence to the bolt-receiving structure as the spacer attempts to rotate with the bolt head.
As can be readily appreciated by those familiar with the assembly of structural components, difficulty often is encountered in performing simple assembly techniques utilizing headed, screw-threaded bolts, because of torsional stresses induced in bolt-receiving structure as a consequence of torque applied to the heads of the bolts and transmitted to the structure through spacers, as the juxtaposed surfaces of the heads, spacers, and structure are brought into frictional engagement.
Such difficulties often are encountered, for example, in spacecraft assembly operations, wherein because of imposed weight limitations, structural components frequently are designed to withstand only expected forces applied to the structure during lift-off. Unfortunately, such components are subject to failure simply because of the existence of torsional stresses induced as a consequence of the tightening of certain bolts employed during assembly operations.
Additionally, as can be appreciated by those familiar with the fabrication and assembly of structure wherein bolts must be snugged-down in the assembly of components supported for rotation about an axis substantially paralleling the longitudinal axis of the bolts, a great deal of difficulty often is experienced in supporting such components against rotation induced as a consequence of torque transmitted thereto through spacers, such as washers and the like, interposed between the heads of the bolts and the adjacent surfaces of the components. For example, such difficulties often are experienced in the installation of propeller bolts, the torquing of axle bolts, a tightening of steam cylinder heads, and similar operations.
Finally, in instances wherein a bolt must be inserted and snugged-down in a space to which limited access is afforded, a great deal of difficulty often is encountered in inserting a bolt and washer into a bolt-receiving opening, such as an internally threaded bore. Consequently, the time expended in performing even simple assembly operations often results in increased labor costs because of the increased time required to perform such an operation.
2. Description of the Prior Art
Gear head wrenches, often referred to as torque wrenches and as torque multipliers, are notoriously old. Such devices, of course, are provided with a planetary gear train which serves to multiply input torque of the wrench. Such wrenches are provided with reaction bars attached to housings provided for the gear trains and are utilized to support the housings against rotary motion reactively induced as torque is applied to the input of the wrench for tightening threaded fasteners, such as bolts and the like.
Unfortunately, wrenches of the aforementioned type often are difficult to employ simply because reaction bars must be manipulated simultaneously with the input of torque to the torque input shaft, thus requiring that additional space be made available in which to manipulate the wrench. Moreover, and quite importantly, such wrenches simply include no means for isolating bolt-receiving structure from stress resulting from torque applied to the bolt head and transmitted through an interposed spacer, as the bolt is snugged-down.
It is, therefore the purpose of the instant invention to provide a gear head wrench having a capability of applying counter-torque to a spacer and adapted to be employed simply and efficiently for rapidly installing, in bolt-receiving structure, headed bolts circumscribed by annular spacers, such as washers, lugs, bosses and the like, while isolating the bolt-receiving structures from torque-induced stress.